Won't start sometimes?

Having issues with my 99 Tacoma not starting every time. My positive battery cable is loose (I know, I need to replace it), but I don't think thats the main issue. There's a black wire that seems to be the issue that comes off the terminal and connects to a terminal on a small (one inch) gray box, that has another wire connected to the other terminal on the same small gray box. the two wires (one white, one black) then makes its way through the firewall. When I wiggle that black wire that comes off the positive battery terminal, there's a spark, and thats what let's me start the truck (only about half the time). Usually takes me 5-10 wiggles of the small wire confused, before it starts.

Anyone know what's going on here? I am not the original owner, so I don't know if this is aftermarket stuff. It seems like it is. Fusible link?

Here's a link to a video I uploaded to YouTube for reference:

https://youtu.be/XadxKaFNv9U

 

Hey, just saw your video. The two things I would try first are to remove any accessories from the positive terminal that aren't 100% necessary. I'm not sure what that little box is that you were showing.

I'd also make sure the positive connection is nice and tight.

I know you said you wiggle that wire and that gets it to be able to start. What exactly is that hooked up to?

 

I honestly have no idea what that wire connects to. It goes through the firewall, but beyond that, I'm not sure.

The truck did have an amp installed with a subwoofer. I thought it might have something to do with that, but the only cable that I know that goes from the engine bay to the cab, is the speaker cable that goes directly to the amp (that same cable can be seen in the video, its the very top-most cable connected to the positive terminal with the cable wrap around it)

 

Hmmm so the other cable just ends before the firewall? I had a similar situation without the starting issues, but I had a 20 year old amp under my seat. When it started cutting out, I decided to pull it and realized it was never fused!!! Check and see if you have that kind of situation too. Another question. Have you put a multi-meter in line with your battery to see if you have any parasitic loss?

 

The black and white cables, as well as the speaker cable, go through the firewall. The speaker cable is in fact fused under the hood, although I still can't get power to the amp. I replaced the old amp fuse receptacle with a new one, as the old one blew and i didnt notice, and the under the hood fuse receptacle and fuse melted together. But, I can easily follow the speaker cable to the amp, but the black and white cables go up under the trim right under the steering wheel area, but I can't follow them all the way reaching by hand.

I did notice when I was down there just now, that there are a couple of holes in the plastic underneath the steering wheel area (I'll attach a picture) where it looks like something used to be mounted, I have no idea what though.

I'll have to take the trim off tomorrow when I have more time to investigate.

I haven't checked anything with a multimeter. I do have one, but I am a total dunce when it comes to anything electrical.

 

Yeah I'd check for any parasitic draw from accessories. Use this video to guide you: https://www.youtube.com/watch?v=KF1gijj03_0
You just put your multimeter in line with the negative cable and terminal and check for any amp draw.

Then I'd remove those accessories from the positive cable altogether and see what that does and tighten up and CLEAN those battery terminal and the connections.

Provide updates!

 

That loose clamp is no bueno. It may appear to not attenuate voltage but likely limits current, i.e. cause more voltage drop under load. In the near term I would cram something such as stripped bare speaker wire between post and clamp then hammer the clamp on to get consistent contact. Years ago I used a metal bicycle seatpost shim as a semi-permanent fix. Then get rid of as much rando wiring as possible.

 

Your batt is probably dying and that loose connection on the positive terminal makes mechanics cry

Edit:
I just read through this thread and there's all these suggestions about tracing down the parasitic current loss.

It's a '99. It needs a new battery and a tight terminal connection

 

Yeah, I suggested that because it can happen on any vehicle especially with aftermarket accessories. I just traced down some parasitic loss on my 99 a few weeks ago. It was an accessory (OBDII plug in) that I always left in, but for some reason it began drawing current recently while the truck was off. You never know. Quick and easy test